Newark Mayor Cory Booker, a Democrat, is running for the U.S. Senate against Republican Steve Lonegan. / Mel Evans, AP

by Catalina Camia, USA TODAY

by Catalina Camia, USA TODAY

Democrat Cory Booker is still up by 10 points over Republican Steve Lonegan in a new poll on the New Jersey Senate race, but the Newark mayor's lead is shrinking with the special election just two days away.

A Monmouth University poll released Monday shows Booker with a 52%-42% lead over Lonegan among likely voters - with 12% saying they are undecided or could change their mind before Wednesday's special election.

In Monmouth's poll two weeks ago, Booker had a 13-point edge over his GOP rival - down from 16 points this summer. His favorability ratings also dropped for the third month in a row in Monmouth polling.

President Obama is urging New Jersey voters to get out and vote for his friend, in a new video that touts Booker's leadership.

Booker is still the favorite to succeed Frank Lautenberg, a Democrat who died in January. The Monmouth poll shows a majority of voters, 55%, believe the Newark mayor's views on issues are more in line with New Jersey than those of Lonegan (37%).

New Jersey also hasn't elected a Republican to the Senate since 1972. Thanks to his frequent TV appearances and social media networking, Booker is perhaps better known to voters than Lonegan. The Republican is a former Bogota mayor and ex-state director for Americans for Prosperity, the conservative group backed by the Koch brothers, and lost a GOP gubernatorial primary in 2009 to Chris Christie.

But it's precisely Booker's high profile that may be hurting him. Monmouth's polling shows 48% of likely voters say Booker wants to be a U.S. senator to be "on the national stage," vs. 37% who say he wants to serve New Jersey. Seven percent of likely voters say Booker wants both equally.

"Concerns about Cory Booker's intentions to serve New Jersey continue to persist and his favorability ratings continue to drop," says Patrick Murray, director of the Monmouth University Polling Institute. "At the same time, voters clearly prefer Booker's political views over Lonegan's. The message seems to be that Garden State voters don't like to feel that their support is being taken for granted."